A number of prior art devices exist which are used in a ball return system for returning a bowling ball to a bowler. Common to each of these devices is some means by which the bowling ball enters a lifting device, is lifted to a desired level, and then is ejected from the device to a waiting bowler.
One representative example of a prior art device is U.S. Pat. No. 5,449,327 to Heddon, et al. The system disclosed in this reference includes a conventional power lift device which includes a pair of tubular track members which receive and guide the bowling ball as it is lifted to a specified height.
U.S. Pat. No. 3,127,172 to Troiano, et al. discloses a mechanism for returning bowling balls from the alley pit to the players' area. The mechanism includes a pair of vertically disposed wheels and a guide way including a pair of tubular rods which are spaced equidistant from the outer peripheral edge of the wheels. A bowling ball is introduced in the space between the guide way and the lower wheel. The spinning action of the lower wheel and the upper wheel carries the bowling ball upwards to a specified height along the pair of rods where the ball is then ejected onto a platform.
U.S. Pat. Nos. 3,109,648 to Anderson, et al., and 3,313,540 to Unteidt disclose bowling ball lift mechanisms including a pair of continuous rod-like track members which secure a bowling ball against lower and upper rotating wheels. The wheels cause the bowling ball to be lifted along the track members. The track members are arcuately curved concentrically about the axis of rotation of each of the wheels.
U.S. Pat. Nos. 3,109,649 to Anderson, et al., and 3,479,029 to Zuercher, et al. both disclose bowling ball lift mechanisms which make use of a pair of tubular track members to engage the bowling ball as it is lifted to a specified height by a rotating lift wheel.
U.S. Pat. No. 2,682,405 to Huck discloses a ball lift apparatus including a pair of track members arranged in an S-shaped pattern. A conveyor belt disposed in a vertical position is spaced from the track members. The bowling ball enters one end of the apparatus and is engaged by the conveyor belt. The track members are spaced from the conveyor belt such that a bowling ball is caught between the conveyor belt and track members in order to lift and deposit the ball to a specified height.
Examples of prior art commercial devices include the Century C-90 Ball Lift which includes a pair of tubular track members, and the Brunswick Subway Power Lift assembly which makes use of a pair of conventional tracks with wear strips which may be replaced when worn.
While each of the foregoing inventions may be suitable for their intended purposes, one common disadvantage is that the dual or pair of track members are difficult to remove and replace when worn. Additionally, since there are always a pair of track members used in conjunction with a lifting mechanism, excessive wear on one track member may require that the pair be replaced as even the slightest amount of uneven wear between the track members can create problems for effectively lifting the bowling ball.